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| author | Přemysl Eric Janouch <p@janouch.name> | 2025-05-07 19:42:46 +0200 |
|---|---|---|
| committer | Přemysl Eric Janouch <p@janouch.name> | 2025-05-07 19:42:46 +0200 |
| commit | b69d3f8692b1d34f9b8616e046cdabe0d2fb67c0 (patch) | |
| tree | bbbeb4fa30762d2f6b68f738c0d34691c1ba590a | |
| parent | 9a26284a642252d678809bbbf299b8f31d81416e (diff) | |
| download | liberty-b69d3f8692b1d34f9b8616e046cdabe0d2fb67c0.tar.gz liberty-b69d3f8692b1d34f9b8616e046cdabe0d2fb67c0.tar.xz liberty-b69d3f8692b1d34f9b8616e046cdabe0d2fb67c0.zip | |
LibertyXDR: add support for default in unions
| -rw-r--r-- | libertyxdr.adoc | 6 | ||||
| -rw-r--r-- | tests/lxdrgen.lxdr | 2 | ||||
| -rw-r--r-- | tools/lxdrgen.awk | 29 |
3 files changed, 30 insertions, 7 deletions
diff --git a/libertyxdr.adoc b/libertyxdr.adoc index d3255ed..0002184 100644 --- a/libertyxdr.adoc +++ b/libertyxdr.adoc @@ -93,10 +93,12 @@ and always-present field, which must be a tag *enum*: case CAR: void; case LORRY: i8 axles; case PLANE: i8 engines; + default: void; }; -All possible enumeration values must be named, and there is no *case* -fall-through. +There is no *case* fall-through. +Unless *default* is present, only the listed enumeration values are valid. +Any *default* must currently be empty. Framing ------- diff --git a/tests/lxdrgen.lxdr b/tests/lxdrgen.lxdr index d332336..8bfa8f7 100644 --- a/tests/lxdrgen.lxdr +++ b/tests/lxdrgen.lxdr @@ -25,5 +25,7 @@ struct Struct { union Onion switch (Enum tag) { case NOTHING: void; + default: + void; } o; }; diff --git a/tools/lxdrgen.awk b/tools/lxdrgen.awk index 5a51d2d..b3bb696 100644 --- a/tools/lxdrgen.awk +++ b/tools/lxdrgen.awk @@ -1,6 +1,6 @@ # lxdrgen.awk: an XDR-derived code generator for network protocols. # -# Copyright (c) 2022 - 2023, Přemysl Eric Janouch <p@janouch.name> +# Copyright (c) 2022 - 2025, Přemysl Eric Janouch <p@janouch.name> # SPDX-License-Identifier: 0BSD # # Usage: env LC_ALL=C awk -f lxdrgen.awk -f lxdrgen-{c,go,mjs}.awk \ @@ -218,7 +218,7 @@ function defstruct( name, d, cg) { } function defunion( name, tag, tagtype, tagvalue, cg, scg, d, a, i, - unseen, exhaustive) { + unseen, defaulted, exhaustive) { delete cg[0] delete scg[0] delete d[0] @@ -249,9 +249,22 @@ function defunion( name, tag, tagtype, tagvalue, cg, scg, d, a, i, if (!unseen[tagvalue]--) fatal("no such value or duplicate case: " tagtype "." tagvalue) codegen_struct_tag(tag, scg) + } else if (accept("default")) { + if (tagvalue) + codegen_union_struct(name, tagvalue, cg, scg) + + expect(accept(":")) + if (defaulted) + fatal("duplicate default") + + tagvalue = "" + defaulted = 1 } else if (tagvalue) { if (readfield(d)) codegen_struct_field(d, scg) + } else if (defaulted) { + if (readfield(d)) + fatal("default must not contain fields") } else { fatal("union fields must fall under a case") } @@ -259,11 +272,17 @@ function defunion( name, tag, tagtype, tagvalue, cg, scg, d, a, i, if (tagvalue) codegen_union_struct(name, tagvalue, cg, scg) - # Unseen cases are simply not recognized/allowed. + # Unseen cases are only recognized/allowed when default is present. exhaustive = 1 for (i in unseen) - if (i && unseen[i]) - exhaustive = 0 + if (i && unseen[i]) { + if (defaulted) { + codegen_struct_tag(tag, scg) + codegen_union_struct(name, i, cg, scg) + } else { + exhaustive = 0 + } + } Types[name] = "union" codegen_union(name, cg, exhaustive) |